The present invention relates to determination of flow regime, an important consideration in a variety of mixed phase flows, including boiling water conduits and many other applications. The state of the art of flow regime determination for boiling water conduits, particularly associated with power plants is set forth in the final report (NP 118) prepared by Heat Transfer and Fluid Flow Service of the Atomic Energy Research Establishment of Harwell, England, for the Electric Power Research Institute, 3412 Hillview Avenue, Palo Alto, Cal. 94304, U.S.A., dated March 1976 entitled "Experimental Methods in Two-Phase Flow Studies." That paper reports the state of the art as comprising, for purposes of flow regime determination, visual and photographic methods, contact methods, electrochemical measurements in re shear stresses, X-ray fluctuations, pressure fluctuation analysis and multi-beam X-ray methods. None of these methods have achieved wide-spread acceptance nor have shown themselves to be wholly adequate in terms of all the relevant criteria.
It is an important object of the present invention to provide a new method of flow regime detection combining reliability of measurement with high measurement speed, usability under various void fraction concentration conditions, adaptability to a variety of fluids, nondisturbance of the flow condition to be determined, all consistent with low bulk, weight and cost of associated equipment.